用两个栈实现队列

public class reconstructionQueue {
    
    Stack<Integer> stack1 = new Stack<Integer>();
    Stack<Integer> stack2 = new Stack<Integer>();
    
    public void push(int node){
        stack1.push(new Integer(node));
    }
    
    public int pop(){
        if(stack2.isEmpty()){
            while(!stack1.isEmpty()){
                stack2.push(stack1.pop());
            }
        }
        return stack2.pop().intValue();
    }
}